1. Technical Field of the Invention
The present invention relates to a compressor blade, and more particularly, to a compressor stator blade and a compressor rotor blade.
2. Description of the Related Art
In a gas turbine or a jet engine, a compressor for compressing an air introduced from the outside is configured as a multi-stage axial flow type compressor in which a rotor blade row and a stator blade row are alternately combined.
In the multi-stage axial flow type compressor, a radial inner end part (hub side) of a stator blade constituting the stator blade row or a radial outer end part (tip side) of a rotor blade constituting the rotor blade row includes a gap (clearance) between each facing surface and itself, and a leakage flow (clearance flow) flowing through the clearance is a factor causing deterioration in performance of the compressor.
Thus, Patent Documents 1 and 2 have already disclosed methods of reducing the leakage flow (clearance flow) or its influence.
A shroud integrated rotor blade disclosed in Patent Document 1 aims to prevent a leakage flow of a gas path.
As shown in FIG. 1, in a shroud integrated type rotor blade 60, a shroud 53 is provided from a front edge 61 of a tip of a rotor blade 52 to a rear edge 62, and a radius of a seal fin tip end 63 is substantially the same as that of a shroud rear edge end 64. In a split ring 65, a radius of an inner peripheral surface 66 is slightly larger than those of the seal fin tip end 63 and the shroud rear edge end 64. As a result, a cavity sectional area 69 existing on the downstream side of a seal fin 57 can be reduced between an outer surface 56 of the shroud 53 and an inner peripheral surface 66 of the split ring 65. For this reason, as for a leakage flow 67 passing through an empty space in the vicinity of a throat from a gas path 55, the flow is shut off by the inner peripheral surface 66 of the split ring 65. In this manner, even when the shroud 53 of a winglet type is used, a leakage flow 67 of the gas path 55 can be prevented.
A shroud segment disclosed in Patent Document 2 aims to promote a simplification of an aircraft engine and a decrease in weight of the aircraft engine by suppressing an increase in the number of components of the aircraft engine.
As shown in FIG. 2, honeycomb cells 74 and 75 allowing the contact thereof with tip fins 72 and 73 of a turbine blade 71 are integrally formed with the rear surface of a back plate 70. A jet shield 76 allowed to collide with a jet J of burned gas leaking between the honeycomb cells 74 and 75 and the tip fins 72 and 73 is integrally formed at the rear end part of the back plate 70.
[Patent Document 1]
Japanese Patent Application Laid-Open No. 2002-371802 “Shroud Integrated Type Rotor Blade and Split Ring of Gas Turbine”
[Patent Document 2]
Japanese Patent Application Laid-Open No. 2005-30316 “SHROUD SEGMENT”
FIGS. 3A to 3E are views showing a flow field on the stator blade hub side of a convention structure. In these drawings, FIGS. 3A and 3B are views in the case of a both-end-support stator blade, FIGS. 3C and 3D are views in the case of a stator blade mounted with a hub clearance, and FIG. 3E is a view in the case of a stator blade mounted with a spindle.
FIG. 3A is a side view showing the both-end-support stator blade. In this drawing, a both-end-support stator blade 1A includes a radial outer end (tip side) fixed to an inner surface of a stationary body such as a casing and a radial inner end (hub side) fixed to a hub shroud 2A. Additionally, a labyrinth 4 is provided between the hub shroud 2A and an inner rotary body 3 so as to seal a part therebetween.
FIG. 3B is a top view showing the blade row of the both-end-support stator blade. In this case, since a clearance flow does not occur at a position on the tip side and the hub side of the stator blade 1A, a low energy fluid 5 is accumulated in a negative pressure surface corner part of each stator blade 1A. Here, the low energy fluid indicates a fluid in which a speed is low and a swirl or a separation occurs. Since a flow is dispersed at the negative pressure surface of the stator blade by the existence of the low energy fluid 5, a performance of the stator blade deteriorates.
FIG. 3C is a side view showing the stator blade mounted with the hub clearance. In this drawing, a stator blade 1B mounted with the hub clearance includes a radial outer end (tip side) fixed to an inner surface of a stationary body such as a casing and a radial inner end (hub side) located so as to have a gap from the inner rotary body 3. That is, the stator blade 1B mounted with the hub clearance includes a hub-side gap (hub clearance 6A) between the rotary body 3 and itself.
FIG. 3D is a top view showing the blade row of the stator blade mounted with the hub clearance. In this case, a clearance flow 7 flowing through the hub clearance 6A occurs at a position on the hub side of the stator blade 1B. Since the clearance flow 7 flows from a pressure surface of the stator blade 1B to a negative pressure surface, as shown in FIG. 3B, the low energy fluid 5 accumulated in the negative pressure surface corner part moves toward the pressure surface side of the adjacent blade due to the clearance flow 7. As a result, the low energy fluid 5 is accumulated at a position on the pressure surface side of each stator blade 1B. Since a flow is dispersed at the pressure surface of the stator blade by the existence of the low energy fluid 5, a performance of the stator blade deteriorates.
FIG. 3E is a side view showing the stator blade mounted with the spindle. In this drawing, the stator blade 10 mounted with the spindle includes a radial outer end (tip side) fixed to an inner surface of a stationary body such as a casing and a radial inner end (hub side) fixed to a stationary part via a spindle mechanism 15. Although the stator blade 10 mounted with the spindle includes a hub-side gap (hub clearance 6B) between the stationary part and itself, since the facing surface is in a stationary state, a clearance flow hardly occurs.
For this reason, the top view showing the blade row of the stator blade mounted with the spindle is the same as that of FIG. 3B, and the low energy fluid 5 is accumulated in the negative pressure surface corner part of each stator blade. Since a flow is dispersed at the negative pressure surface of the stator blade by the existence of the low energy fluid 5, a performance of the stator blade deteriorates.
The above-described problems also occur in the compressor rotor blade.
FIGS. 4A to 4D are views showing a flow field on the rotor blade tip side of a conventional structure. In this drawing, FIGS. 4A and 4B are views in the case of a rotor blade mounted with a shroud, and FIGS. 4C and 4D are views in the case of a rotor blade mounted with a clearance.
FIG. 4A is a side view showing the rotor blade mounted with the shroud. In this drawing, a rotor blade 8A mounted with the shroud includes a radial inner end (hub side) fixed to the inner rotary body 3 and a radial outer end (tip side) fixed to a tip shroud 2B. Additionally, the labyrinth 4 is provided between the tip shroud 2B and an outer stationary body so as to seal a part therebetween.
FIG. 4B is a top view showing the blade row of the rotor blade mounted with the shroud. In this case, since a clearance flow does not occur at a position on the tip side and the hub side of the rotor blade 8A, the low energy fluid 5 is accumulated in the negative pressure surface corner part of each rotor blade 8A. Since a flow is dispersed at the negative pressure surface of the rotor blade by the existence of the low energy fluid, a performance of the rotor blade deteriorates.
FIG. 4C is a side view showing the rotor blade mounted with the clearance. In this drawing, a rotor blade 8B mounted with the clearance includes a radial inner end (hub side) fixed to the inner rotary body 3 and a radial outer end (tip side) located so as to have a gap from the outer stationary body. That is, the rotor blade 8B mounted with the clearance includes a tip-side gap (tip clearance 6B) between the outer stationary body and itself.
FIG. 4D is a top view showing the blade row of the rotor blade mounted with the clearance. In this case, the clearance flow 7 flowing through the tip clearance 6B occurs at a position on the tip side of the rotor blade 8B. Since the clearance flow 7 flows from a pressure surface of the rotor blade 8B to a negative pressure surface, as shown in FIG. 4B, the low energy fluid 5 accumulated in the negative pressure surface corner part moves toward the pressure surface side of the adjacent blade due to the clearance flow 7. As a result, the low energy fluid 5 is accumulated at a position on the pressure surface side of each rotor blade 8B. Since a flow is dispersed at the pressure surface of the rotor blade by the existence of the low energy fluid 5, a performance of the rotor blade 8B deteriorates.